With recent improvements in semiconductor devices, there is a desire for techniques for mounting a semiconductor element on a wiring board to form a face-down structure (e.g., flip chip method or direct chip attachment method). The flip chip method has a problem concerning the reliability of connecting parts because a semiconductor element and a wiring board, which differ from each other in coefficient of linear expansion, are directly connected to each other electrically. A technique which is being employed as a measure in eliminating this problem comprises filling the space between a semiconductor element and a wiring board with a liquid resin material and curing the material to form a cured resin. Thus, the stress concentrating on the electrical connecting parts is dissipated into the cured resin to thereby improve connection reliability. In the flip chip method employing solder bumps, the technique heretofore in use for filling with a liquid material comprises first mounting a flip chip on a wiring board to form metallic junctions through a solder melting step and then injecting a liquid resin material into the space between the semiconductor element and the wiring board based on a capillary effect. This process for semiconductor device production has a problem that the productivity is low because it involves many production steps.